Need help with User Exit in Validation

Hi,

I need help while creating a Validation (FMVABD) to validate that while using Transaction Code FR10 (Budget Release of Funds Center), only that User which is maintained in Funds Center Master data can release the budget.

I have written followin Code in Users Exit:

<CODE>

b_result = B_FALSE.

SELECT SINGLE * FROM FMFCTR WHERE BOSSID = SY-UNAME AND FICTR = '??????'.

IF SY-SUBRC = 0.

b_result = B_TRUE.

ENDIF.

</CODE>

'??????' In the second condition of WHERE CLUASE I want to mention Fund Center for which Budget is being released.

Kinldy assist how to do that.

Regards,

Hanif